Major Difference/error? In The Swedish Version Of "the Gunslinger"

I wonder if, when he originally wrote the story, if he just wasn't yet capable of defining the character of Roland as he is. What I mean is, perhaps King knew all or some of the things about Roland that he later changed originally. Mayhap he didn't think it was vital to the story back then, but changed his mind? Who knows. I like to think that Roland didn't change much from first version to last, but that King added stuff that he already knew. Who knows?